Tempering device for vehicle seats

ABSTRACT

A tempering system ( 3 ) for the tempering of at least one contact surface ( 5 ) of a vehicle seat ( 1 ) coming into contact with a user, having at least one tube ( 7 ), at least partially located near the contact surface ( 5 ), with a cooling medium ( 9 ), which flows through the tube ( 7 ) in a closed circuit. In the region of the contact surface ( 5 ) the tube ( 7 ) is at least partially shielded from the user by a rubber-elastic protective layer ( 11 ).

TECHNICAL FIELD

The present invention relates to a tempering device for tempering a contact surface of a vehicle seat, the tempering device being a tubular, closed-loop system with a cooling medium flowing therethrough. Devices of this kind cool the seat of a vehicle in summer and heat it in winter.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 5,921,314 discloses a seat through which air flows in order to bring it to a comfortable temperature. However, it is not possible to produce airflow through certain seats because, for example, they are covered with a leather cover. Other, non-porous surfaces also prevent or restrict airflow.

DE 4,432,497 discloses a seat having a cooling circuit. This cooling circuit employs a liquid which flows through hoses to carry heat away from the seat surface. However, installing hoses in the seat cushion is expensive. In addition, liquid-cooled seats are especially susceptible to inadvertent or unintentional damage of the seat. For example, the cooling medium can leak during the life of the seat. Thus, long-term system integrity is difficult to ensure.

There is thus a need for tempering systems for seats which ensure efficient tempering, reasonable cost to manufacture and reliable long-term operation.

SUMMARY OF THE INVENTION

In one embodiment, a tempering system is provided for tempering at least one seat surface contacted by an occupant. The tempering device includes at least one tube, at least partially located near the contact surface, and a cooling medium flowing through the tube in a closed circuit. In the region of the contact surface, the tube is at least partially shielded from the occupant by a protective layer which may be rubber-elastic. The present tempering system offers increased protection for cooling hoses in the seat surface. In addition, it is ensured that, even in the event of escape of the cooling liquid, the surface of the seat coming into contact with the user remains dry.

In another embodiment, the tube is at least partially embedded, and can be cast, in the protective layer. This embodiment permits simplified assembly. A tube, which is embedded in the protective layer, may be installed jointly with the protective layer. In addition, in the event of damage to the tube, the protective layer can also serve as a secondary wall to retain the cooling medium.

The protective layer can have a thickness of between 4 and 60 mm, and preferably is at least 15 mm. The tube can have an outer cross-sectional diameter of between 5 and 20 mm, and preferably is at least 10 mm. Such dimensional limits, which are given only as examples, permit very sturdy construction.

The tube can also be at least partially formed by the protective layer. In this way, the number of component parts can be reduced, and the protective layer and tube can be produced in a single operation.

The protective layer may be made, at least partially, of silicone, rubber, latex, synthetic gel, polyurethane gel and/or rubber, and admixtures of carbon fibers or metal fibers. This produces an inexpensive protective layer with high resistance to tearing. Further, additional physical properties of the protective layer are selectively adjustable by admixtures.

In a further embodiment, the protective layer includes a seat occupancy detector. This is advantageous in that it permits the integration of a plurality of subsystems in one structural unit. In cases of capacitive-type occupancy detectors, the protective layer can act as a dielectric or at least one plate of the capacitive sensor can be located on a surface of the protective layer. In another example, two plates of the capacitive sensor are located on opposite surfaces of the protective layer. Integrating the seat occupancy sensor into the protective layer simplifies production of the overall system.

In another example, the seat occupancy detector comprises a fluid-filled cavity within the protective layer, and a pressure sensor. The fluid may be liquid or air. The fluid pressure signal indicates the occupancy status of the seat.

In another example, the seat occupancy detector comprises a first photoconductor for the introduction of light and a second photoconductor for the absorption of light, each located on the protective layer which is at least partially transparent in the region of the photoconductors. Light passing from the first to the second photoconductor passes through the transparent region of the protective layer. The amount or intensity of the detected light is a function of the pressure load upon the seat. This embodiment is advantageous in that few additional components are required to provide for the seat occupancy detector.

Other objects and advantages will become apparent with reference to the following detailed description, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this invention reference should now be had to the embodiments illustrated in greater detail in the accompanying figures and described below by way of examples of the invention wherein:

FIG. 1 shows a top view of a seat with a tempering system according to an embodiment of the present invention in partial longitudinal section.

FIG. 2 shows an enlarged cross section through the protective layer of the tempering system of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is described with respect to an tempering system for a vehicle seat, the present invention may be adapted and utilized for tempering other components such as arm rests, door trim, armature panels, steering wheels, as well as non-automotive seat and tempered components applications. In the following description, various operating parameters and components re described for several embodiments. These specific parameters and components are included as examples and are not meant to be limiting.

FIG. 1 shows a vehicle seat 1 with a seat part 2 and a backrest 4. In the exemplary embodiment these are covered with a non-perforated leather cover 6. The seat part 2 has a contact surface 5, which is usually occupied by a passenger when the seat is in use.

A tempering system 3 is located in the seat part 2. Of course, it could also be provided in the backrest portion 4. The tempering system 3 has a tube 7, which is made of an elastic but pressure-resistant material, for example rubber, silicone, PVC or gel of synthetic material. The tube 7 advantageously is located meanderingly or in a substantially sinusoidal manner in a section located under the contact surface 5. The tube 7 is positioned to run just under the cover 6.

In the region of the contact surface 5, the tube 7 is covered over, at least toward the cover 6, by a protective layer 11 which may be rubber-elastic. In the present example, the tube 7 is completely embedded, such that it is liquid-tight, in the protective layer 11 and is completely enclosed by the protective layer 11. This results in a sturdy and, at the same time, elastic surface module, which is simple to install in the seat part 2. The tube 7 can be cast in the protective layer 11. The tube 7 can also be at least partially formed by the protective layer 11. That is, the protective layer 11 can be cast with hollow channels forming fluid channels. In such a case, the tube 7 comprises the hollow channel formed in the protective layer 11.

The material of the protective layer should be a tear-resistant, highly elastic material such as for example rubber, silicone or gel of synthetic material. The protective layer may be made, at least partially, of silicone, rubber, latex, synthetic gel, polyurethane gel and/or rubber, and admixtures of carbon fiber or metal fibers. The specific thermal conductivity of the protective layer should be greater than 0.05, such as at least 0.5, and preferably greater than 5 W/km. The thermal conductivity can be adjusted by admixtures of heat-conducting material, for example, metal fibers. The tube material or protective layer which forms the tube 7 should have an elongating or elongation rupture of at least 100%.

The protective layer can have a thickness of between 4 and 60 mm, and preferably is at least 15 mm. The tube can have an outer cross-sectional diameter of between 3 and 10 mm. The distance between the tube 7 and the upper surface of the protective layer should be at least 2 mm thick and can be up to approximately 10 mm thick. The module comprising the protective layer 11 and tube 7 is at least 5 mm thick and can be up to 20 mm thick.

The tube 7 is filled with a cooling medium 9. The cooling medium 9 can be a liquid, preferably of water or alcohol base although other mediums are contemplated. The cooling medium 9 has a freezing point which preferably lies below −20° C., such as below −40° C.

The two ends of the tube 7 are located on the side of the seat part 2 turned away from the user, at a pump 21 located there. In operation, the pump 21 produces circulation of the cooling medium 9 in the tube 7 in a closed circuit.

The tempering system 3, in addition, has an exchange unit 15. The exchange unit 15 has a Peltier element 17 and a blower or fan 19. The Peltier element 17 is located on the tube 7, in order to adjust the temperature of the cooling medium 9 to the desired temperature level. Depending on the polarity of the electrical voltage applied to the Peltier element, the cooling medium 9 is heated or cooled by the Peltier element 17. The fan 19 blows a stream of air on the Peltier element 17 in order to remove waste heat or to supply ambient heat. The exchange unit 15 preferably is placed on a side of the vehicle seat 1 different from the contact surface 5, such as on its back or underside.

The tempering device should be regulated so that the temperature of the contact surface 5 remains at approximately 34° C. or below. The desired temperature could also be set by a user adjustable input such as a switch, rotating dial, or slider.

The tempering system may additionally contain an electric heating element 50. The heating element 50 may be integrated into the protective layer, or be made of an electrically conductive material forming at least part of the protective layer. For example, electrically conductive material forming the heating element may be provided in the region surrounding the tube 7, or may be worked throughout the protective layer 11. In another example, instead of one tube, a plurality of tubes are provided. It may alternatively be advantageous that the protective layer itself form the wall of the tube. It may in addition be provided that the cushion of the seat be made substantially entirely of the rubber-elastic protective layer. For this purpose, the protective layer advantageously has a layer thickness of at least 1 cm. It may alternatively be advantageous to place a corresponding tempering system in the backrest 4. The corresponding exchange unit and/or pump could then be located either on the back of the backrest or the underside of the seat part.

FIG. 2 shows a cross section through the protective layer 11 with additionally integrated seat-occupancy detectors 25, 25′, 25″.

The seat-occupancy detector 25 has a first capacitor plate 29, which is located on the side of the protective layer 11 facing toward the cover 6. The seat-occupancy detector 25 in addition has a second capacitor plate 29′. This is located on the protective layer on the side of the protective layer 11 facing away from the cover 6. The capacitor plates 29, 29′ are in each instance connected, via a conductor 30, 30′, with a measuring circuit, not represented. The capacitor plates 29, 29′ preferably are formed by thin metal layers. These are, for example, printed or vapor-deposited and comprise at least partially silver, copper and/or aluminum.

In operation, an electric voltage is applied to the two capacitor plates 29, 29′, to form a capacitor in which the protective layer 11 acts as a dielectric. If the protective layer 11 is acted on with pressure by a passenger sitting on the seat, the protective layer 11 is pressed together. This alters the distance between the capacitor plates 29, 29′. This results in a change in capacity of the capacitor, detected by the measuring circuit and consequently in a seat-occupied signal.

The seat-occupancy detector 25′ has a cavity 37, in the form of a bubble 37′. The cavity is filled with a measuring fluid 35. In this regard, air or water is advantageous. The cavity 37 is connected via a measuring conduit 36 to a pressure sensor which, for simplicity, is not shown. If the protective layer 11 is pressure-loaded by a passenger, the pressure in the measuring fluid 35 rises. This pressure increase and hence the seat-detection signal can be read via the measuring line 36.

The seat-occupancy detector 25″ has a first photoconductor 39, one end 41 of which is embedded in the protective layer 11. A second photoconductor 39′, one end 41′ of which is likewise embedded in the protective layer 11, is also provided. The two ends 41, 41′ are arranged substantially flush with one another, in order to allow light from one photoconductor 39 to pass into the other photoconductor 39′. In order to permit this passage of light from one photoconductor to the other, at least the region of the protective layer 11 located between the two photoconductor ends 41, 41′ is at least partially transparent. If the protective layer 11 is pressure-loaded, at least one of the photoconductors 41, 41′ is deflected. As a result, the quantity and/or the quality (e.g. color) of the light that has passed is altered. In addition or alternatively, compression of the region of the protective layer 11 located between the two photoconductor ends 41, 41′ produces an altered dispersion of the light within the protective layer 11. This too results in an altered passage of light. An appropriate light sensor can then indicate whether the seat is occupied.

The seat occupancy detectors 25, 25′, 25″ can be used in conjunction with the tempering system to prevent the system from operating or modify system operation absent the presence of a seat occupant. The seat occupancy detectors can also be used in conjunction with other vehicle systems including safety systems. The present tempering system, however, provides an advantageous way of providing or implementing the seat occupancy detectors with only minimal additional components.

While the invention has been described in connection with one or more embodiments, it is to be understood that the specific mechanisms and techniques which have been described are merely illustrative of the principles of the invention, numerous modifications may be made to the apparatus described without departing from the spirit and scope of the invention as defined by the appended claims. 

1. A tempering system for tempering at least one contact surface of a vehicle seat comprising: at least one tube, a portion of which is located proximate the contact surface; a cooling medium flowing through the tube in a closed circuit; and a protective layer shielding the contact surface from the portion of the tube located proximate the contact region.
 2. A tempering system according to claim 1 wherein the tube is at least partially embedded in the protective layer.
 3. A tempering system according to claim 1 wherein the protective layer has a thickness of approximately 4-60 mm, and the tube has an outer diameter of approximately 3-10 mm.
 4. A tempering system according to claim 1 wherein the tube is at least partially formed by the protective layer.
 5. A tempering system according to claim 1 wherein the protective layer at least partially comprises silicone, rubber, latex, synthetic gel, polyurethane gel, or admixtures of carbon fibers or metal fibers.
 6. A tempering system according to claim 1 comprising a seat occupancy detector located on the protective layer.
 7. A tempering system according to claim 6 wherein the seat occupancy detector comprises a capacitive sensor and wherein the protective layer acts as a dielectric and at least one plate of the capacitive sensor is located on a surface of the protective layer.
 8. A tempering system according to claim 7 wherein plates of the capacitive sensor are located on opposite sides of the protective layer.
 9. A tempering system according to claim 1 wherein the protective layer includes a seat occupancy detector comprising a cavity formed in the protective layer and filled with a measuring fluid, and a pressure sensor in communication with the measuring fluid for indicating an occupancy status of the seat.
 10. A tempering system according to claim 1 wherein the protective layer includes a seat occupancy detector comprising a first photoconductor for the introduction of light and a second photoconductor for the absorption of light both located in the protective layer, and wherein the protective layer is at least partially transparent between the first and second photoconductors, and wherein the quantity or quality of light absorbed by the second photoconductor is indicative of a pressure load of the seat.
 11. A vehicle seat comprising: at least one cushion forming a contact surface for a seat occupant; and a tempering system for tempering the contact surface the tempering system comprising at least one tube, a portion of which is located proximate the contact surface, a cooling medium flowing through the tube in a closed circuit, and a protective layer shielding the contact surface from the portion of the tube located proximate the contact region.
 12. A vehicle seat according to claim 11 wherein the at least one cushion is formed by the protective layer.
 13. A vehicle seat according to claim 11 wherein the tube is at least partially embedded in the protective layer.
 14. A vehicle seat according to claim 11 wherein the tube is at least partially formed by the protective layer.
 15. A vehicle seat according to claim 11 comprising a heating element arranged within the protective layer.
 16. A vehicle seat according to claim 11 comprising a seat occupancy detector located on the protective layer.
 17. A vehicle seat according to claim 16 wherein the seat occupancy detector comprises a capacitive sensor and wherein the protective layer acts as a dielectric and at least one plate of the capacitive sensor is located on a surface of the protective layer.
 18. A vehicle seat according to claim 11 wherein the protective layer includes a seat occupancy detector comprising a cavity formed in the protective layer and filled with a measuring fluid, and a pressure sensor in communication with the measuring fluid for indicating an occupancy status of the seat.
 19. A vehicle seat according to claim 11 wherein the protective layer includes a seat occupancy detector comprising a first photoconductor for the introduction of light and a second photoconductor for the absorption of light both located in the protective layer, and wherein the protective layer is at least partially transparent between the first and second photoconductors, and wherein the quantity or quality of light absorbed by the second photoconductor is indicative of a pressure load of the seat.
 20. A vehicle seat comprising: at least one cushion forming a contact surface for a seat occupant; a tempering system for tempering the contact surface the tempering system comprising at least one tube, a portion of which is located proximate the contact surface, a cooling medium flowing through the tube in a closed circuit, and a protective layer shielding the contact surface from the portion of the tube located proximate the contact region, the tube being at least partially embedded within the protective layer; and a seat occupancy detector located in the protective layer, the seat occupancy detector comprising at least one of a capacitive sensor, pressure sensing system, or light sensing system providing a signal indicative of an occupancy status of the vehicle seat. 